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News Flash: Danley Breaks Laws of Physics

post #1 of 7
6/16/12 at 1:46pm
Thread Starter 
New front loaded horn fron Danley apparently employs two 18" drivers and gets 117db with 1w@1m.

100% efficiency in 2pi space is 112.1db with 1w@1m.

This means that Danley is getting 4.9db over 100% efficiency, hence this is the first ever over-unity subwoofer.

Woot.

280
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post #2 of 7
6/17/12 at 8:19am
This is just one of the "typos" that is on the new website.

It should say 2.83V. And since the load is a 2 ohm load (or 2 4ohm loads) the equivilent at 8 ohms would be 6dB less.

On the products that are a 8 ohm nominal impedance-we will be using the 1W (even though you don't "apply" 1W) statement-to keep with normal convention. On the lower impedance models we will be using the 2.83V. This one got overlooked.

Thanks for the catch-we will get it changed
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post #3 of 7
6/17/12 at 9:14am
Quote:
Originally Posted by Ivan Beaver View Post

On the products that are a 8 ohm nominal impedance-we will be using the 1W (even though you don't "apply" 1W) statement-to keep with normal convention. On the lower impedance models we will be using the 2.83V.
I understand why you're doing that; I also post my SPL charts at 2.83v/1m, as what most customers are interested in is how loud Speaker A will go compared to Speaker B using the same amp. But you're going to catch a lot of flack from those who don't understand why, and suffer accusations as has already happened here. I'd put a prominent note on the site, if not on the individual pages, explaining what you're doing and why. You'll still get questioned, but then you can just post a link to the answer.
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post #4 of 7
6/17/12 at 11:38am
Quote:
Originally Posted by Ivan Beaver View Post

This is just one of the "typos" that is on the new website.

Overall, the new site visually appears so much nicer. Details of the visual elements can now be discernible on most all the products. But the technical specs side of things is certainly lacking as compared to the "cut sheet" style of the old site. Some of the existing line appears to be re-worked as well, best of luck with all that.

I still plan a trip to your shop to audition the various aspects of the Danley line, as I can't ever seem to find your products out in either an install, or live touring production. I'd rent an entire rig to check everything out, but the local Pro Audio operators don't carry your stuff. I guess it's possible I've heard your products somewhere, but I'm all eyes everywhere I go where performance audio is concerned, and I typically can recognize the boxes.

Thanks
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post #5 of 7
6/17/12 at 7:31pm
Thread Starter 
"...you're going to catch a lot of flack from those who don't understand why, and suffer accusations as has already happened here."

no accusations have been made. just observations.

bfm, aren't you one of the guys who suggested that 50% efficiency was about the limit for a front loaded horn (one of those keele papers that you posted)?

subtracting 6 from 117 still gives 111db 1w1m, which is about...78% efficiency. hhmmm...

edit: btw, i don't mean to imply the horn is a bad design. it takes the approach of putting an electrical impedance peak right around the kick drum fundamental, which minimizes current through the drivers and maximizes efficiency in its target playback region. subjectively, this is likely why such designs have more "kick" than others even at the same spl. :-)
Edited by LTD02 - 6/17/12 at 7:44pm
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post #6 of 7
6/18/12 at 9:32am
Quote:
Originally Posted by LTD02 View Post

bfm, aren't you one of the guys who suggested that 50% efficiency was about the limit for a front loaded horn (one of those keele papers that you posted)?
subtracting 6 from 117 still gives 111db 1w1m, which is about...78% efficiency. hhmmm...
There are cabinets that have greater than 100% "apparent" effeciency. HOW? As I am sure you are asking.

It has to do with forward directivity. The theoretical numbers assume an omni device. A device that has forward directivity "appears" to be in a smaller space (half quarter ect) than it actually is.

Now this directivity is not even across the intended passband-but it is real and does add to the overall sensitivity.

Here is a model (using our 3d modeling porgram) that has a DBH218 in the middle of a 100x100' space. The plot is centered at 63Hz and is 1 oct wide. The data in our files is measured data-not simulated.

You can clearly see the forward directivity.

DBH218.jpg 54k .jpg file
Edited by Ivan Beaver - 6/18/12 at 11:46am
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post #7 of 7
6/18/12 at 12:55pm
Thread Starter 
i see what you are measuring now. that definitely makes comparisons across subwoofer brands tricky, as now the environment has to be considered as part of the equation. placed in a corner, an omni source will get ~12db loading, while the horn will get much less because it is already pretty directional, so the high sensitivity of the horn should include some sort of caveat that it won't benefit from boundary gain nearly as much as an omni. and like you said, the directivity is going to vary by frequency as is the core sensitivity of the horn, which complicates things twice further. what a mess given how much your customers are likely to focus on "the sensitivity number". i sympathise!
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